1. Field of the Invention
The invention generally relates to a technology of recovering a playing image to a captured image, and more particularly, to a technology able to process the display mode of an image with a motion block therein.
2. Description of Related Art
Usually, the capturing rate of a video is different from the standardized playing rate. For example, a video capturing rate is 24 Hz, while the usual playing rate according to, for example, NTSC standard, is 60 Hz or 50 Hz for PAL & SECAM standards. Hence, in order to play an originally capturing video compliant with NTSC or PAL & SECAM standard, the captured video needs to be pulled down to that of the playing standard.
For example, to change 24 Hz to 50 Hz of PAL standard, a captured image would be unwoven into two images including an even image and an odd image. It's well known that an even image is formed by a plurality of images extracted from a captured image and belonging to the even scan lines; an odd image is formed by a plurality of images extracted from a captured image and belonging to the odd scan lines. In this way, 24 Hz of the capturing rate can be changed to 50 Hz of the playing rate. In other words, a captured original image would be unwoven according to a selected video pattern following the rate required by a playing standard so as to be played in interlaced way.
On the contrary, if a field image to be played needs to be recovered to its originally captured image, the video pattern thereof must be detected out, followed by recovering it into the originally captured image according to the video pattern.
FIG. 1 is a diagram showing how to convert an image captured with a slower rate into an image with a higher playing rate compliant with a playing standard. Referring to FIG. 1, in order to make an image captured in 24 Hz played in a playing rate close to 50 Hz, an original image 100 would be unwoven into an odd image 102 and an even image 104, wherein the odd image 102 is formed by the images belonging to the odd scan lines in the original image 100 and the even image 104 is formed by the images belonging to the even scan lines in the original image 100. During playing, the unwoven images are woven into the played image, for example, the played image on TV. The above-mentioned deweaving way is just the so-called 2:2 mode, and it can be 2:3 mode or other modes as well. Taking the 2:3 mode as an example, an original image 100 is unwoven into an odd image and an even image, followed by deweaving the next original image 100 into odd/even/odd three images.
In terms of a TV display, when a major playing content is playing at the display area thereof, a motion figure, for example, motion textural information, may overlay the bottom of the screen. FIG. 2 is a diagram of a traditional display method of an image with mix mode. Referring to FIG. 2, a major played dynamic image is displayed in a display screen 120. At the time, if there are other additional dynamic images, for example, motion textural information overlaying on the screen 120, it would cover a data portion of the original image 100 belonging to the area. For example, an original image 122 and a motion caption 124 may be simultaneously displayed.
Usually, the original image 122 and the motion caption 124 come from different sources, and they might be different video play modes. Hence, in order to recover the played image to the original video, it is needed to detect and process the moving motion caption 124 so as to obtain the more correct original image data.
In the prior art, for example, U.S. Patent Application No. 2005/0249282 discloses a scheme that an entire frame is divided into a plurality of blocks and a video mode detection is performed on each of the blocks, and for the blocks with mix mode, the conventional Bob method is used for processing. The scheme basically is a block-based video mode detection by using a block as an unit, which requires a larger storage space, where the motion values are individually saved and the detection result of mix mode is based on block as an unit.
In addition, U.S. Patent Application No. 2009/0256958 discloses a scheme that a square mix mode range is obtained through combining the motion state with the video detection result. However, the mix mode range does not take a pixel as a unit and the mix mode is unhelpful for detecting video. In particular, when the mix mode range is excessive, it may leads to failing of the video detection.
In short, the recover method to process a mix mode video is still in developing.